**7.3. Phosphorus**

The highest dose of phosphorus should be applied to the bottom of planting grooves. Such application at a greater depth increases the nutrient uptake by sugarcane, since water availability at the subsurface varies less than on the surface. The mobility of phosphorus in the soil is small, and its diffusion is influenced by several factors, especially precipitation by cations such as iron, aluminum, and calcium; volumetric content of water in the soil; adsorption of phosphorus by soil colloids; complexity of the environment structure; soil compaction; distance to reach roots; and contents of elements in soil [21]. In general, very low values are recorded for transport of phosphorus due to its strong interaction with soil colloids, especially in very weathered soils. According to [21], it can be estimated that the transport is on average 0.013 mm per day.

Even applying a higher dose of phosphorus during planting, there is a need for phosphate fertilization for regrowth. **Tables 3**–**5** present recommendations for phosphate fertilization of plant cane at the bottom of planting grooves, considering the extractor used in the soil chemical analysis, Mehlich or ion exchange resin, as well as soil fertility classes.

According to some authors, it is unlikely to obtain a productivity above 150 t when the phosphorus extracted with resin is lower than 6.0 mg dm−3. However, in studies conducted in newly developed Cerrado areas in the northwest of Minas Gerais on a phosphorus content lower than 6.0 mg dm−3, yields were higher than 200 tons of culms per hectare in a plant cane with a 14-month cycle fertilized with 100 kg of P per hectare and receiving complementary irrigation of only 120 mm [1].

Phosphorus applied during sugarcane planting ensures, in most cases, an adequate supply of this element to plant cane and the first regrowth. Formulations containing P in the fertilization of later regrowth should be used. Prior to phosphate fertilization, the soil should be analyzed at the 0–20 cm layer and, if the base saturation (V) is less than 50%, it is recommended to perform first a liming to raise the V to 60%. As shown in **Table 1**, the absence of exchangeable aluminum in the soil solution increases the efficiency of phosphate fertilization, especially since there is no formation of aluminum phosphate (a low solubility compound) in the soil

and within plant roots. If the base saturation is greater than 50% and the P content, extracted

**Table 5.** Phosphorus doses suggested for sugarcane fertilization based on the availability of phosphorus extracted with

**Production expectation in the cane plant cycle (t ha−1) Soil fertility class**

, multiply the desired value by 2.29.

, multiply the desired value by 2.29.

ion exchange resin and on the expectation of natural matter production.

Less than 100 70 — — 100–150 80 60 40 150–180 90 70 50 Above 180 100 80 60

**Table 4.** Phosphorus doses suggested for sugarcane fertilization based on the availability of phosphorus extracted with

**Production expectation in the cane plant cycle (t ha−1) Extracted phosphorus (mg dm−3)**

Less than 100 80 44 30 20 100–150 90 55 40 26 Above 150 100 66 45 35

The dose of phosphorus used may be based on the recovery of the P removed by harvesting. In this case, for each ton of natural material, 200–300 g of P should be applied. If, for example, the production of natural regrowth material was 120 t per ha, which corresponds to about 100 t of industrializable culms, from 25 to 40 kg of P should be applied per ha. Phosphate fertilizer should be applied together with N and K. In large crops, regrowth N-P-K fertilization is carried out simultaneously with subsoiling and cultivation of interlines. In small and medium properties, especially those where burnt sugarcane is harvested or produced for animal feed, the furrowing of sugarcane lines using an animal traction plow for later fertilization has presented good results. The N-P-K fertilizer is applied to open grooves in sugarcane interlines

Potassium fertilization of sugarcane is carried out at planting and after each sugarcane cut because potassium is displaced in the soil profile. The mineral fertilization of sugarcane is based on the results of soil analysis at the 0–20 cm layer, on the productivity desired and on the final use of sugarcane. In sugarcane fields intended for cattle feeding, the potassium dose

, a regrowth phosphate fertilization is recommended.

**Low Medium High**

Mineral Nutrition and Fertilization of Sugarcane http://dx.doi.org/10.5772/intechopen.72300 181

**0–6 7–17 16–40 >40**

**Dose of P (kg ha−1)\***

**Dose of P (kg ha−1)\***

with Mehlich, is lower than 10 mg/dm3

O5

and then covered with soil using animal traction.

**7.4. Potassium**

\*

\*

To convert P into P2

To convert P into P2

Source: adapted from [8].

O5

Mehlich and on the expectation of natural matter production.


**Table 3.** Soil fertility classes considering clay, phosphorus, and potassium contents extracted with Mehlich.


**Table 4.** Phosphorus doses suggested for sugarcane fertilization based on the availability of phosphorus extracted with Mehlich and on the expectation of natural matter production.


Source: adapted from [8].

urea in the soil, irrigate it, or fertilize it before a rain, one should choose ammoniacal sources,

The highest dose of phosphorus should be applied to the bottom of planting grooves. Such application at a greater depth increases the nutrient uptake by sugarcane, since water availability at the subsurface varies less than on the surface. The mobility of phosphorus in the soil is small, and its diffusion is influenced by several factors, especially precipitation by cations such as iron, aluminum, and calcium; volumetric content of water in the soil; adsorption of phosphorus by soil colloids; complexity of the environment structure; soil compaction; distance to reach roots; and contents of elements in soil [21]. In general, very low values are recorded for transport of phosphorus due to its strong interaction with soil colloids, especially in very weathered soils. According to [21], it can be estimated that the transport is on average 0.013 mm per day.

Even applying a higher dose of phosphorus during planting, there is a need for phosphate fertilization for regrowth. **Tables 3**–**5** present recommendations for phosphate fertilization of plant cane at the bottom of planting grooves, considering the extractor used in the soil chemi-

According to some authors, it is unlikely to obtain a productivity above 150 t when the phosphorus extracted with resin is lower than 6.0 mg dm−3. However, in studies conducted in newly developed Cerrado areas in the northwest of Minas Gerais on a phosphorus content lower than 6.0 mg dm−3, yields were higher than 200 tons of culms per hectare in a plant cane with a 14-month cycle fertilized with 100 kg of P per hectare and receiving complementary

Phosphorus applied during sugarcane planting ensures, in most cases, an adequate supply of this element to plant cane and the first regrowth. Formulations containing P in the fertilization of later regrowth should be used. Prior to phosphate fertilization, the soil should be analyzed at the 0–20 cm layer and, if the base saturation (V) is less than 50%, it is recommended to perform first a liming to raise the V to 60%. As shown in **Table 1**, the absence of exchangeable aluminum in the soil solution increases the efficiency of phosphate fertilization, especially since there is no formation of aluminum phosphate (a low solubility compound) in the soil

**Clay content (g kg−1) Low Medium High**

0–150 Less than 20 20–30 Above 30 150–350 Less than 15 15–20 Above 20 350–600 Less than 10 10–15 Above 15 600–1000 Less than 5 5–10 Above 10

Less than 40 41 a 90 Above 90

Available phosphorus classification (mg dm−3)

Available potassium classification (mg dm−3)

**Table 3.** Soil fertility classes considering clay, phosphorus, and potassium contents extracted with Mehlich.

cal analysis, Mehlich or ion exchange resin, as well as soil fertility classes.

such as ammonium sulfate, or nitric sources.

**7.3. Phosphorus**

180 Sugarcane - Technology and Research

irrigation of only 120 mm [1].

**Table 5.** Phosphorus doses suggested for sugarcane fertilization based on the availability of phosphorus extracted with ion exchange resin and on the expectation of natural matter production.

and within plant roots. If the base saturation is greater than 50% and the P content, extracted with Mehlich, is lower than 10 mg/dm3 , a regrowth phosphate fertilization is recommended.

The dose of phosphorus used may be based on the recovery of the P removed by harvesting. In this case, for each ton of natural material, 200–300 g of P should be applied. If, for example, the production of natural regrowth material was 120 t per ha, which corresponds to about 100 t of industrializable culms, from 25 to 40 kg of P should be applied per ha. Phosphate fertilizer should be applied together with N and K. In large crops, regrowth N-P-K fertilization is carried out simultaneously with subsoiling and cultivation of interlines. In small and medium properties, especially those where burnt sugarcane is harvested or produced for animal feed, the furrowing of sugarcane lines using an animal traction plow for later fertilization has presented good results. The N-P-K fertilizer is applied to open grooves in sugarcane interlines and then covered with soil using animal traction.

#### **7.4. Potassium**

Potassium fertilization of sugarcane is carried out at planting and after each sugarcane cut because potassium is displaced in the soil profile. The mineral fertilization of sugarcane is based on the results of soil analysis at the 0–20 cm layer, on the productivity desired and on the final use of sugarcane. In sugarcane fields intended for cattle feeding, the potassium dose to be applied should be increased, since nutrient removal will be greater because sugarcane is harvested along with nodes and dry leaves. The amount of potassium contained in nodes and dry leaves of sugarcane ranges around 70 kg per ha [22] and may reach 140 kg per ha in plant cane [3]. **Tables 6**–**8** present the recommendations of potassium fertilization for plant cane and regrowth, with Mehlich or ion exchange resin as extractors.

The dose of K to be applied to regrowth may be based on the recovery of the potassium removed by the crop, as suggested for nitrogen and phosphate fertilization. This method was adopted by the authors and has been recommended with excellent agronomic and financial results. Although the absorption and the removal of potassium vary among sugarcane cultivars, it can be considered that for each ton of natural matter harvested, there is, on average, a removal of 1.5 kg of K. There is no need to partition the potassium used in regrowth fertilization due to possible losses by leaching. In studies conducted by Oliveira et al. [3] using lysimeters, K losses by leaching were not reported (**Figure 6**). These results were confirmed by [23], who also observed that K losses by percolation below a depth of 100 cm were 9.0 kg ha−1, totally compensated by the input of K from rainwater (18 kg ha−1).


\* To convert K into K2 O, multiply the desired value by 1.20. When sugarcane is harvested for animal feed, it is suggested to raise the recommended K dose by 25%.

**Table 6.** Potassium doses suggested for sugarcane fertilization based on the availability of potassium extracted with Mehlich and on the expectation of natural matter production.

> Potassium chloride has been the most used source of K in fertilization. However, other residues containing potassium are also used, among them vinasse, a by-product of alcohol manufacture. Vinasse may replace potassium fertilization. Therefore, the amount of potassium supplied by application of vinasse should be fully deducted from mineral fertilization. The volume of vinasse applied ranged from 60 to 300 m3 ha−1 depending on the potassium concentration. The concentration of K in vinasse originating from molasses is higher than in others, followed by a mixed must, which contains on average twice as much K as in vinasse originating from sugar-

**Figure 6.** Solution volume and mass of percolated nitrogen during the plant cane cycle cultivated in a sandy soil.

Sulfur can be dispensed in areas that received application of vinasse or agricultural gypsum. The

PO4 ) 2

500 mg L−1, is 10 mg/dl3

 **dm−3)**

Mineral Nutrition and Fertilization of Sugarcane http://dx.doi.org/10.5772/intechopen.72300 183

**0–1.5 1.6–3.0 >3.0**

**Dose of K (kg ha−1)\***

. In areas in

cane juice, with values ranging between 2.5 and 1.2 kg m−3, respectively (**Table 9**).

−2 in the soil, extracted with Ca(H<sup>2</sup>

**Regrowth production expectation (t ha−1) K extracted with resin (mmolc**

O, multiply the desired value by 1.20.

Less than 60 90 60 30 60–80 110 80 50 80–100 130 100 70 Above 100 150 120 90

**Table 8.** Potassium doses suggested for regrowth fertilization based on the availability of potassium extracted with ion

**7.5. Sulfur**

\*

To convert K into K2

Source: adapted from [8].

exchange resin and on the expected production.

critical level of S-SO4


**Table 7.** Potassium doses suggested for sugarcane fertilization based on the availability of potassium extracted with ion exchange resin and on the expected production.


\* To convert K into K2 O, multiply the desired value by 1.20. Source: adapted from [8].

to be applied should be increased, since nutrient removal will be greater because sugarcane is harvested along with nodes and dry leaves. The amount of potassium contained in nodes and dry leaves of sugarcane ranges around 70 kg per ha [22] and may reach 140 kg per ha in plant cane [3]. **Tables 6**–**8** present the recommendations of potassium fertilization for plant

The dose of K to be applied to regrowth may be based on the recovery of the potassium removed by the crop, as suggested for nitrogen and phosphate fertilization. This method was adopted by the authors and has been recommended with excellent agronomic and financial results. Although the absorption and the removal of potassium vary among sugarcane cultivars, it can be considered that for each ton of natural matter harvested, there is, on average, a removal of 1.5 kg of K. There is no need to partition the potassium used in regrowth fertilization due to possible losses by leaching. In studies conducted by Oliveira et al. [3] using lysimeters, K losses by leaching were not reported (**Figure 6**). These results were confirmed by [23], who also observed that K losses by percolation below a depth of 100 cm were 9.0 kg

**Low Medium High**

 **dm−3)**

**0–0.7 0.8–1.5 1.6–3.0 3.1–6.0 >6.0**

**Dose of K (kg ha−1)\***

**Dose of K (kg ha−1)\***

cane and regrowth, with Mehlich or ion exchange resin as extractors.

ha−1, totally compensated by the input of K from rainwater (18 kg ha−1).

**Production expectation in the cane plant cycle (t ha−1) Soil fertility class**

\*

\*

To convert K into K2

Source: adapted from [8].

exchange resin and on the expected production.

To convert K into K2

182 Sugarcane - Technology and Research

to raise the recommended K dose by 25%.

Mehlich and on the expectation of natural matter production.

Less than 90 100 — — 90–120 120 100 80 120–150 140 120 100 150–180 160 140 120 Above 180 180 160 140

**Table 6.** Potassium doses suggested for sugarcane fertilization based on the availability of potassium extracted with

**Production expectation in the cane plant cycle (t ha−1) K extracted with resin (mmolc**

O, multiply the desired value by 1.20.

Less than 100 120 100 60 60 0 100–150 160 140 100 80 0 Above 150 200 160 120 100 0

**Table 7.** Potassium doses suggested for sugarcane fertilization based on the availability of potassium extracted with ion

O, multiply the desired value by 1.20. When sugarcane is harvested for animal feed, it is suggested

**Table 8.** Potassium doses suggested for regrowth fertilization based on the availability of potassium extracted with ion exchange resin and on the expected production.

**Figure 6.** Solution volume and mass of percolated nitrogen during the plant cane cycle cultivated in a sandy soil.

Potassium chloride has been the most used source of K in fertilization. However, other residues containing potassium are also used, among them vinasse, a by-product of alcohol manufacture. Vinasse may replace potassium fertilization. Therefore, the amount of potassium supplied by application of vinasse should be fully deducted from mineral fertilization. The volume of vinasse applied ranged from 60 to 300 m3 ha−1 depending on the potassium concentration. The concentration of K in vinasse originating from molasses is higher than in others, followed by a mixed must, which contains on average twice as much K as in vinasse originating from sugarcane juice, with values ranging between 2.5 and 1.2 kg m−3, respectively (**Table 9**).

#### **7.5. Sulfur**

Sulfur can be dispensed in areas that received application of vinasse or agricultural gypsum. The critical level of S-SO4 −2 in the soil, extracted with Ca(H<sup>2</sup> PO4 ) 2 500 mg L−1, is 10 mg/dl3 . In areas in


to Mehlich-1 and HCl extractors. According to [24], there is a tendency for DTPA to be more efficient than Mehlich-1 and HCl in situations where the availability of Zn and Cu is changed by liming. As for Mn, acid and chelating solutions have shown very close correlation coefficients between Mn in soil and in plants. However, by analyzing soils fertilized with Mn

Mineral Nutrition and Fertilization of Sugarcane http://dx.doi.org/10.5772/intechopen.72300 185

**Figure 7.** Solution volume and mass of percolated potassium during the plant cane cycle cultivated in a sandy soil.

**Table 10** lists the minimum levels of micronutrient availability in soil extracted with DTPA and Mehlich-1 solution, below which such microelements should be supplied to plants by fertilization. The doses of copper, zinc, manganese, and iron to be applied, in case of deficiency, are 2.5–6.0, 5.0–7.0, 3.0–6.0, and 6.0–10.0 kg ha−1, respectively, using oxides, chlorides, and sulfates. In studies conducted by the authors on coastal plain soils in Alagoas, northeastern Brazil, it was verified that even when high-dose manganese and copper sulfates (up to 16.0 kg of element/ ha) were applied, RB867515 and RB92579 remained deficient in these elements. The content

oxides, there was a tendency of DTPA being the best extractor.

**DTPA Mehlich-1**

Available Cu Zn Mn Fe Cu Zn Mn Fe

Low ≤0.2 ≤0.5 ≤1.2 ≤4 ≤0.8 ≤1.0 ≤6 ≤19 Medium 0.3–0.8 0.6–1.2 1.3–5.0 5–12 0.8–1.2 1.0–1.5 6–8 19–30 High >0.8 >1.2 >5.0 >12 >1.2 >1.5 >8 >30

**Table 10.** Minimum values of micronutrient availability in the soil extracted with a solution of DTPA and Mehlich-1.

**Extractor**

Element

mg dm−3

Source: cited by [1].

Source: Analyses carried out by the authors on the vinasse of mills located in Minas Gerais and Alagoas, Brazil.

**Table 9.** Chemical composition of vinasse originating from different musts.

need of this macronutrient, at least 30 kg of sulfur per hectare should be applied using ammonium sulfate or simple superphosphate, which contains, respectively, approximately 210 and 110 g of S per kg of fertilizer (**Figure 7**).

#### **7.6. Micronutrients**

In most areas cultivated with sugarcane in Brazil, there has been an adequate supply of micronutrients in the soil, thus dispensing their use in chemical fertilizations. However, the implantation of sugarcane plantations in less fertile or marginal areas, associated with fertilization using concentrated fertilizers and the planting of high productivity varieties, which increasingly increase the absorption and export of nutrients, has caused micronutrient deficiency in several sugarcane plantations. In such cases, there is a need for the supply of microelements by fertilization. Soil analysis and area and variety history have been used as predictive methods for assessing the possibility of occurrence of micronutrient deficiency. Soil analysis should be associated to area and variety history since analytical results are influenced by the extractor used, by the characteristics of the soil and of the variety, and also by the time of sample collection. There are reports of marked effects of soil moisture on micronutrient contents [1, 5].

Studies carried out by [24] showed that the best correlations between the Zn or Cu contents in soils and the concentrations of these micronutrients in plants were obtained by the method that uses a solution of diethyl triamine penta-acetic acid (DTPA) as extractor when compared

**Figure 7.** Solution volume and mass of percolated potassium during the plant cane cycle cultivated in a sandy soil.

to Mehlich-1 and HCl extractors. According to [24], there is a tendency for DTPA to be more efficient than Mehlich-1 and HCl in situations where the availability of Zn and Cu is changed by liming. As for Mn, acid and chelating solutions have shown very close correlation coefficients between Mn in soil and in plants. However, by analyzing soils fertilized with Mn oxides, there was a tendency of DTPA being the best extractor.

**Table 10** lists the minimum levels of micronutrient availability in soil extracted with DTPA and Mehlich-1 solution, below which such microelements should be supplied to plants by fertilization. The doses of copper, zinc, manganese, and iron to be applied, in case of deficiency, are 2.5–6.0, 5.0–7.0, 3.0–6.0, and 6.0–10.0 kg ha−1, respectively, using oxides, chlorides, and sulfates.

need of this macronutrient, at least 30 kg of sulfur per hectare should be applied using ammonium sulfate or simple superphosphate, which contains, respectively, approximately 210 and

Source: Analyses carried out by the authors on the vinasse of mills located in Minas Gerais and Alagoas, Brazil.

**Molasses Mixed Cane juice**

de vinasse

de vinasse

Fe 52–120 47–130 45–110 Cu 3.1–9.3 4.2–57.3 1.0–18.0 Zn 3.0–4.0 3.0–4.0 2.0–3.0 Mn 6.0–11.0 5.0–11.0 5.0–10.0 pH 4.2–4.4 3.6–4.4 3.5–3.8

N 0.57–0.79 0.33–0.48 0.25–0.35 P 0.05–0.15 0.03–0.14 0.03–0.07 K 3.27–6.32 1.81–2.78 0.95–1.61 Ca 1.32–1.70 0.40–0.95 0.08–0.52 Mg 0.50–0.85 0.19–0.35 0.13–0.25 S 0.30–0.40 0.45–0.54 0.58–0.70 Organic matter 37.0–57.0 19.1–45.1 15.3–34.7

In most areas cultivated with sugarcane in Brazil, there has been an adequate supply of micronutrients in the soil, thus dispensing their use in chemical fertilizations. However, the implantation of sugarcane plantations in less fertile or marginal areas, associated with fertilization using concentrated fertilizers and the planting of high productivity varieties, which increasingly increase the absorption and export of nutrients, has caused micronutrient deficiency in several sugarcane plantations. In such cases, there is a need for the supply of microelements by fertilization. Soil analysis and area and variety history have been used as predictive methods for assessing the possibility of occurrence of micronutrient deficiency. Soil analysis should be associated to area and variety history since analytical results are influenced by the extractor used, by the characteristics of the soil and of the variety, and also by the time of sample collection. There are reports of marked effects of soil moisture on micronutrient contents [1, 5].

Studies carried out by [24] showed that the best correlations between the Zn or Cu contents in soils and the concentrations of these micronutrients in plants were obtained by the method that uses a solution of diethyl triamine penta-acetic acid (DTPA) as extractor when compared

110 g of S per kg of fertilizer (**Figure 7**).

**Chemical composition Origin of must**

184 Sugarcane - Technology and Research

kg of the element by m3

g of the element by m3

**Table 9.** Chemical composition of vinasse originating from different musts.

**7.6. Micronutrients**

In studies conducted by the authors on coastal plain soils in Alagoas, northeastern Brazil, it was verified that even when high-dose manganese and copper sulfates (up to 16.0 kg of element/ ha) were applied, RB867515 and RB92579 remained deficient in these elements. The content


**Table 10.** Minimum values of micronutrient availability in the soil extracted with a solution of DTPA and Mehlich-1.

of these nutrients in the +3 leaf limbus, used to evaluate nutritional status, was lower than 5.0 and 40.0 mg/kg of dry matter, respectively, for copper and manganese, characterizing a severe deficiency of these elements. The high adsorption of copper and manganese sulfates may have been the cause of the absence of responses. Ref. [25] studied the adsorption of copper originating from several compounds. These authors studied the application of CuSO4 to sandy and humic soils. They found a very high adsorption (99.4%) of copper 2 h after its addition to the soil. On the other hand, copper in the ethylene diaminotetraacetic acid and diaminocyclohexane tetraacetic acid forms presented a soil percentage adsorption of 7.3 and 5.3, respectively. Therefore, it is necessary to evaluate the efficiency of other sources of copper and manganese because the adsorption of copper and manganese sulfates by the soil was very high. In addition to compromising the productive potential of these varieties, copper and manganese deficiency leads to metabolic changes that compromise the quality of the broth. These nutrients are constituents of the polyphenol oxidase and amylase metalloenzymes [17, 26, 27]. Therefore, with a poor performance of these enzymes, there is accumulation of phenolic and starch compounds.

drying is not possible, the samples should be sent quickly to the laboratory where they will be analyzed. **Table 11** lists the nutrient concentration ranges considered adequate accord-

Mineral Nutrition and Fertilization of Sugarcane http://dx.doi.org/10.5772/intechopen.72300 187

Green fertilization is the cultivation of plants for the purpose of incorporating them into the soil. Among the desirable characteristics of a plant to be used as green manure, we may mention the possibility of mechanization from sowing to seed harvesting, absence of dormant seeds, vigorous and deep root system, ability to associate with nitrogen fixing bacteria in atmospheric air, fast growth to control weeds, and presence of mechanisms or synthesizing

Several legumes have these characteristics, but generally there is a preference for *Crotalaria juncea* in the Center-South region of Brazil and for *Crotalaria spectabilis* in the states of Alagoas and Pernambuco, northeastern Brazil. *Crotalaria juncea* is a legume with a very fast initial growth, which provides it with a great competition potential with weeds. However, it is very sensitive to nictoperiods, early blooming in growing nights and, consequently, interrupting growth. Therefore, when cultivating for green manure, sowing should be performed in early October, or as soon as possible. However, for seed production, it should be sown in March. In studies conducted by [1] in two regions of Minas Gerais, Alto Paranaíba and Zona da Mata, there was accumulation of dry matter (DM) by *Crotalaria juncea* sown in October, around 15 tons per hectare, with nitrogen concentration oscillating around 20 g of N per kg of DM. Thus, for a DM yield of 15 t ha−1, the amount of N fixed and/or recycled is 300 kg per hectare. In areas densely infested with *Brachiaria plantaginea*, the inclusion of *Crotalaria* in the system increased the mass of N over the soil by 320% since the accumulation by the natural vegetation of the fallow area was 66 kg of N per ha, while in the area with *Crotalaria*, this accumulation exceeded 250 kg ha−1, a sufficient quantity to ensure a production of 230 t of natural matter of sugarcane per hectare. Ref. [1] reported that in experiments conducted in areas where *Crotalaria* was incorporated into the soil, there was an increased productivity in plant cane of 15 t of culms per hectare compared to fallow areas.

The dry matter production of *Crotalaria juncea* and *spectabilis* in the states of Alagoas and Pernambuco oscillated around 4.5 t of DM per ha. This low production of DM, compared to that observed in the Center-South region, is mainly because the sowing season occurred at the beginning of the rainy season, between April and early May, therefore in longer nights. In Alagoas, in areas where *Crotalaria spectabilis* is used as green manure, it has been common to perform direct grooving without previous soil plowing, similar to the minimum cultivation

Straw is the main crop residue. There are also several types of waste from the industrialization of sugarcane, among them vinasse, filter cake, boiler ashes, and bagasse, which are routinely used in fertilization as sources of nutrients and organic matter. The amount of

compounds that aid in the control of pests, such as nematodes, and diseases.

ing to Brazilian researchers.

**9. Green fertilization**

systems adopted for some other crops.

**10. Crop residues and sugarcane agribusiness waste**
